Laser projection alignment systems often are used in connection with the assembly of large assemblies, such as aircraft. Laser projection alignment systems are used to project illuminated lines onto surfaces of subject articles. The projection of lines is useful to identify the desired location of component parts or features, such as the precise location of a hole to be drilled, for example. However, a laser projection alignment system must first be calibrated to a desired 3D computer model of the assembly, so that the lines are projected in precise desired locations relative to the assembly. To calibrate a laser projection alignment system, laser projection alignment targets, typically six, are positioned in known, precise positions that correspond to coordinates associated with a 3D computer model of the assembly. For example, laser projection alignment targets may be positioned precisely relative to holes or other structures that are associated with the 3D computer model of the assembly being assembled. The laser projection device may then be sequentially aimed at a subset of these targets, typically four, so that the laser projection alignment system detects the position of these targets relative to the laser projection device. The laser projection alignment system can then automatically determine, or find, the remaining targets, typically two. If the remaining targets are appropriately located by the laser projection alignment system, then calibration was successful. On the other hand, if the remaining targets are not successfully located, then calibration was not successful, and adjustments can be made until a desired confidence level is achieved. Examples of laser projection alignment systems are disclosed in U.S. Pat. Nos. 7,015,459 and 7,158,241, the contents of which are incorporated herein by reference.
During assembly of large assemblies, such as aircraft, it may be important to avoid foreign object damage, such as damage resulting from loose tools, loose fasteners, loose scraps, and the like becoming hidden or otherwise trapped in regions of the assembly. For example, in the context of an aircraft, if a tool or portion of a tool is dropped behind a bank of insulation, the tool or portion must be retrieved, which may require disassembly of components parts that took significant time and resources to install in the first instance.